For decades, large corporations requiring always-available computing and data storage resources have housed their computing resources in secure data centers to ensure maximum uptime and availability of their equipment and information.
If you have computing equipment hosted in a data center, then it is stated that you are co-locating your equipment in that facility (colo and colocation are the recognized terms). By hosting your Mac at MacStadium, it will always be available for you to access remotely via screen sharing, VNC, or command line interface from anywhere on the internet.
Many of our clients use their Macs for game servers, web hosting, database hosting, off-site backup, email hosting, or any other applications typically run on macOS.
You can also use your Mac as a Windows server, BSD Server, IP PBX, or any other variety due to its industry standard Intel-based hardware platform.